1. Field of the Invention
This invention relates to thin film perpendicular magnetic head structures. Specifically, the invention relates to structures for cooling nanowires that aid in writing data to high coercivity media.
2. Description of the Related Art
As bit areal densities in magnetic recording continue to progress in an effort to increase the storage capacity of hard disc drives, magnetic transition dimensions and recording head critical features are continuing to shrink. To make the recording medium stable at higher areal bit densities, magnetically harder medium materials with higher coercivity are required. Typically, writing to a harder medium is achieved by increasing the saturation magnetization of the magnetic material comprising the inductive write head; however, current technology is rapidly reaching the limits of known materials in this regard. A further consequence of higher areal densities is an increase in data rates. At very high data writing rates, it becomes increasingly difficult to switch the magnetization of the recording medium using a conventional write field as well as the magnetization of the conventional write pole.
One technology proposed to overcome these difficulties is the wire assisted magnetic recording head (WAMR) which utilizes a single nanowire surrounding three sides of a pole tip. If used as the only magnetic field producing element, the nanowire has the potential to produce higher writing speeds and data rates (due to its lower inductance). In such devices, the nanowire is the main coil for writing the data signals to the media. In other devices, an RF AC signal is added to the data signal being written by the nanowire to aid in switching the media. One of the main difficulties of using a nanowire to write data is the very large current densities required to generate a strong magnetic write field. These high current densities produce high temperatures in the nanowire which may lead to unwanted diffusion and electromigration in the nanowire. In an attempt to control temperatures, heat sink structures located at the ABS are employed to cool the wire as well as deliver current to the wire element itself However, due to the small cross sectional area of the nanowire element, cooling by conduction out of the wire is of limited utility.
Improved methods and structures for writing data to high coercivity media are needed.